What makes our teeth resilient to wear and tear

Published: Tuesday, April 14, 2009, 15:34 [IST]

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Washington, Apr 14 (ANI): Despite all the crunching and munching at every meal, our teeth remain stronger to go under some more tests each day, and now researchers have attributed this resilience to the microscopic "basket-weave" structure of human tooth enamel.

Tooth enamel, which forms the outer coating of teeth, is a strong but brittle substance.

Although the brittleness of teeth is comparable to that of glass, they can last a lifetime without cracking to pieces.

"It's a bit of a mystery as to why they don't just fall apart," Live Science quoted co-author of the new study Brian Lawn, of the National Institute of Standards and Technology, as saying.

For the study, the researchers extracted teeth from humans, sea otters and a few other animals, and subjected them to loading from a metal rod, sort of a worst-case scenario bite.

Lawn explained that the study was aimed to "see how much force [the teeth] could withstand before they break."

The team found that the basket-weave-like microstructure of the enamel kept any cracks that did form from propagating through the enamel and breaking apart the tooth.

This finding explains why dentists can examine the teeth of older people and find that "the teeth are full of cracks, and yet the teeth remain intact," said Lawn.

Enamel thickness and the size of teeth can also affect how resilient they are to a lifetime of chomping.

Anthropologists could use the above information about enamel to piece together dental evolution in primates and animals in general.

They can even use it to speculate what early humans might have chowed down on.

The structure of enamel could also be used to develop similarly resilient substances, including better replacement teeth.

The study has been published in the latest issue of the journal Proceedings of the National Academy of Sciences. (ANI)